No DVB-T signal - No terrestrial TV signal. I am looking for a reason.

At my friend's, some fitter laid TV-SAT about 5 years ago. The SAT signal is there, and the terrestrial TV signal DVB-T disappeared simultaneously on 3 TV sets because they are connected to the same antenna. The first suspicion fell on the power supply which is connected to one of the plugs / TV sets.
This is a ZZA-7 power supply with a crossover (described as a + 12V crossover), which is probably the original for the Telmor Antenna ... I don't know if the power supply diode was lit on the power supply before, but at the moment it is off ... so I took off the plug where the power supply is connected and the voltage is measured ... the meter shows 9V - is it the correct voltage? I know that antenna amplifiers are usually powered with a voltage in the range of 5-12V or maybe even 0-12V ... and I do not know how it is in this case, maybe this 12V is required? The plug also has such a spiral wire, on the plus wire, between the power supply and the cable wire ... I measured behind this spiral, maybe it causes a voltage drop and 9V is ok and should I look elsewhere for a problem? Only with this one receiver is the power supply, in the other two the cable is directly connected to the wall socket. I also found a box, something probably a multiswitch with the symbol AZR / 1-69 / 4 ... now after the symbol I read that it is an antenna splitter, powered by 12V ... so probably the wrong voltage is reaching this splitter? I mean the 9V from this ZZA-7 power supply ...
Can any spec confirm my assumptions? Because I do not know whether to order a new power supply, or maybe this splitter, or climb specifically on the roof and measure the antenna directly? Thank you in advance for any hint ...

demienko wrote:

I don't know if the power supply LED was lit on the power supply before, but it is not lit at the moment ...

And it should shine.

The power supply is to be 12V and the end (if it is a 12V power supply, it is written on the housing). You have to start from this.

Yes, the power supply is described as 12V. The power supply specification also says that it gives 12V / 100mA. So, I think the diagnosis was successful - the ZZA-7 power supply is kicked, which, above all, does not supply the AZR / 1-69 / 4 splitter which, according to specification needs a 12V power supply ... In that case I will replace the power supply and let me know what the effect is Unless someone else adds something Thanks in advance for your suggestions ...

demienko wrote:

In that case, I will replace the power supply and let me know the effect Unless someone else adds something Thanks in advance for your suggestions ...

Well, the power supply is a few dozen zlotys and the cost of repair (part) is pennies.
But with these amounts I recommend a new one

I close the topic. After replacing the power supply, everything returned to normal, i.e. my analysis was correct.
Thanks for confirming some information I don't often deal with such topics, so I prefer to be sure.
greetings